1. Field of the Invention
The invention relates to a laser diode, and particularly relates to a laser diode having better efficiency.
2. Description of Related Art
FIG. 1 is a cross-sectional schematic view illustrating a conventional laser diode. Referring to FIG. 1, a conventional laser diode 10 includes a substrate 11, a first semiconductor layer 12, an emitting layer 13, a second semiconductor layer 14, a patterned insulating layer 15, a first electrode 16, a second electrode 17, and two conductive wires 18. The first semiconductor layer 12 is disposed on the substrate 11. The emitting layer 13 is disposed on a part of the first semiconductor layer 12. The second semiconductor layer 14 is disposed on the emitting layer 13 and forms a ridge mesa. The patterned insulating layer 15 covers a part of the second semiconductor layer 14. The first electrode 16 is disposed on the first semiconductor layer 12, the second electrode 17 is disposed on an area of the second semiconductor layer 14 that is not covered by the patterned insulating layer 15, and one end of each of the conductive wires 18 respectively extend from the first electrode 16 and the second electrode 17.
As shown in FIG. 1, the conventional laser diode 10 is electrically connected to an external part through bonding wire. Due to the consideration of cost, non-metal substrates such as a sapphire substrate, for example, may be chosen as the substrate 11. However, the laser diode using this kind of substrate has difficulty in releasing heat generated during an operation from a substrate end or a bonding wire end, which may result in undesirable heat dissipation performance, and thus influence a working efficiency of the laser diode.